SEA-FLOOR DEPOSITS. PART I 325 



Station 265. 20. vii. 27. Lat. 33 06' 30" S. Long. 16 32' E. 1620 m. (Plate XVII, inset.) 

 Glauconitic mud. A pale, fine-grained sediment, mainly flocculent material in which are scattered 

 Foraminifera and a few sand grains. The flocculent material seems to be in part comminuted fora- 

 miniferal shells together with coccoliths and rhabdoliths, in part decayed organic matter. The 

 minerals are chiefly quartz and glauconite, but both are scarce. The Foraminifera are mainly 

 Glokigerina. 



This and the preceding sample (St. 264) are classified in the official Station List as Globigerina 

 ooze. But as Foraminifera by no means form the bulk of the deposit, the sediments are here regarded 

 as glauconitic mud, with a subordinate proportion of foraminiferal debris. 



Station 283. 13. viii. 27. Off Annobon, Gulf of Guinea. 075 to 1 mile N 12 E of Pyramid 

 Rock, Annobon. 18-30 m. 



Shell sand. The sand consists of foraminiferal and small molluscan shells which average about 

 1 mm. in diameter. Some of the Foraminifera (e.g. Cristellaria) are larger than this, but the shells 

 of Globigerina are smaller ; large textularians are also conspicuous. Few mineral grains occur. 



Station 363. 26. ii. 30. 2-5 miles S 8o° E of south-east point of Zavodovski Island, South 

 Sandwich Islands. 329 m. (Plate XVII.) 



Fine sand. The bulk of the sample is a dark brown sand, the grains reaching a diameter of 0-5 mm. 

 and ranging downwards in size, the average being about 025 mm. Much of the material consists of 

 brown volcanic glass in sharply angular fragments, and many of the grains are vesicular: the sand 

 owes its dark colour to this material. Quartz grains (also up to 0-5 mm. diameter) appear to be more 



rounded. 



The fine-grained material, which has formed a film on the sand in the storage jar, is a mixture of 

 tiny mineral particles and diatomaceous debris. Fragilaria and Thalassiothrix appear to be the most 

 abundant genera, while centric forms {Coscinodiscus and Thalassiosira) are not especially common in 

 occurrence. 



Station 366. 6. iii. 30. 4 cables south of Cook Island, South Sandwich Islands. 340m. (Plate XVII.) 

 Fine sand. A dark brown, nearly black, sand composed almost entirely of fragments of quartz and 



volcanic glass. In size the grains range from a diameter of about o-i mm. to exceedingly small particles. 



Most of the grains are markedly angular in shape, though some have suffered a slight degree of 



rounding. A subordinate quantity of flocculent material gives a green colour to the preserving liquid. 



The presence of sponge spicules and frustules of Coscinodiscus, Cocconeis and Fragilaria is noted. 



The deposit is similar to that from St. 363, but is rather finer in grain. 



Station 425. 4. ix. 30. Lat. 34 50' S to 34 53! ' S. Long. 26 \i\' E to 26 30V E. 4107 m. 



Globigerina ooze. The sample is perhaps more sandy than usual in a typical ooze. Tests of 

 Globigerina and Orbulina are abundant and well developed. Diatoms and sponge spicules also occur, 

 but the former are not numerous. Coccoliths are abundant in the finer fraction, while rhabdoliths 

 (as usual) are less in evidence. 



Station 1165. 4. iii. 33. Lat. 40 547' S. Long. 9° 25-5' E. 4642 m. (Plate XVII.) 

 Radiolarian ooze. This is a brownish mud composed largely of organic debris, with some ad- 

 mixture of sand grains which are generally less than 0-05 mm. in diameter. The coarser fraction 

 consists mainly of radiolarian tests, among which sphaeroid forms are dominant, discoid forms are of 

 common occurrence, while nasselarians are comparatively rare. The genera recognized are Ceno- 

 sphaera, Carposphaera, Xipkosphaera, Hexastylus, Heliodiscus, Porodiscus, Hymeniastrum, Rhopa- 

 lastrum and Lithostrobus. Some Foraminifera {Globigerina), diatoms (Coscinodiscus), and anchor-shaped 

 spines of the holothuroidean Synapta are noted. 



